Receive the latest national-international updates in your inbox

Evacuations have been ordered for low levels of Oroville, California, and several areas downstream from Lake Oroville because of erosion on the Oroville Dam's auxiliary spillway, according to the Butte County Sheriff's Office.

(Published Sunday, Feb. 12, 2017)

With stormy weather approaching, state water managers announced Thursday they will resume releasing water down a damaged spillway at the nation's tallest dam.

The badly eroded main spillway at California's Oroville Dam hasn't been used since March 27. Workers have been reinforcing the massive concrete chute in hopes of protecting it from further damage during the remainder of the wet winter season.

Major repairs are expected to begin later this spring and could take up to two years and cost hundreds of millions of dollars.

Nearly 200,000 people were ordered to evacuate Feb. 12 when a second, emergency spillway began breaking apart from floodwaters. To avert a potential disaster, operators released huge amounts of water down the damaged main spillway to lower the level of the lake behind the dam, cutting the flow over the second spillway. Residents were allowed to return home later that week.

Authorities say the dam itself suffered no damage.

Oroville reservoir is the state's second-largest, and anchors the system of aqueducts, canals and pumps that moves water from Northern California to more arid Central and Southern California.

Earlier this month, Gov. Jerry Brown waived some permitting and review requirements to speed up repairs to the main spillway. The state Department of Water Resources, which operates the dam, is reviewing proposals for the work and could award a contract shortly.

Meanwhile, operators will have to carefully manage the lake level, with more rain and melted snow expected to pour in. Releases down the main spillway are scheduled to begin Friday, and last up to two weeks.